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1

The Effect of Different Methods of Fertilization with Ammonium Sulfate and Urea on Yield and Fruit Size of Highbush Blueberry (Vaccinium corymbosum L.)

Braha Sabri Latif, Kullaj Endrit

Ecological Engineering & Environmental Technology

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2024

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Vol. 25, iss. 4

116--124

EN

The objective of this study was to evaluate the effects of liquid fertilization through drip irrigation with nitrogenous (N) fertilizers, including ammonium sulfate and urea, compared to the application of granular fertilizers on highbush blueberry plants (Vaccinium corymbosum L.) cultivar ‘Draper’ during the first three years of fruit production (2020–2022). Planting of the saplings took place in April 2018, distances were 1.1 m within rows and 2.8 m between rows, 3246 shrubs/ ha. Control variants (no fertilization) were identical for both fertilization methods (liquid and granular). The substrate was a mixture of soil, peat, and pine bark in a 1:1:1 ratio. Both types of fertilizers were used at three N rates, which were increased each year as the plants entered into production (70 to 95, 135 to 190, 195 to 270 kg/ha N). In the first year with liquid fertilization, the yield was 3.8 t/ha, while with granular fertilization, it was 2.7 t/ha, indicating a 29% higher yield with liquid fertilization. Additionally, the yield was 14.8% higher with ammonium sulfate compared to urea. The nitrogen concentration in the leaves with liquid fertilization reached 1.78%, while with granular fertilization, it was 1.67%. Moreover, with ammonium sulfate, it was 1.89%, and with urea, it was 1.73%. Overall, the highest total yield ranging from 16.9 to 25.9 t/ha during the first three years of production was achieved when the plants were fertilized with ammonium sulfate or urea at an annual rate of 70–95 kg/ha N. The conducted research found that liquid fertilization is more efficient in maximizing yield and optimizing the amount of nutrients. Liquid fertilizers were evenly distributed using drip irrigation; this uniform application helps ensure that all plants receive the same amount of nutrients.

2

Alkoholiza mocznika jako potencjalna metoda otrzymywania węglanu propylenu na skalę techniczną

Kotyrba Łukasz, Siewniak Agnieszka, Woszczyński Piotr, Nowakowska-Bogdana Ewa, Chrobok Anna

Przemysł Chemiczny

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2022

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T. 101, nr 12

1112--1117.

PL

Przeprowadzono test katalizatorów w procesie syntezy węglanu propylenu metodą alkoholizy mocznika. Spośród katalizatorów cynkowych, cynowych, glinokrzemianowych i MgO największe wydajności reakcji uzyskano, stosując zasadowy węglan cynku (78,9%) i tlenek cynku (76,9%). Badania wykazały, że tlenek cynku nie traci swoich właściwości katalitycznych po kolejnych nawrotach, jednak jego straty po każdym cyklu reakcyjnym wynosiły 27,4 - 33,1%. Dowiedziono, że rozpuszczony w mieszaninie poreakcyjnej cynk może być z niej usunięty za pomocą wymieniaczy jonowych, takich jak ziemia bieląca TONSIL 570 FF lub kationit Purolite CT151.

EN

Propylene glycol, urea and catalyst (compds. of Zn, Mg, Sn or aluminosilicates) were mixed in the flow of N₂, at 150°C, for 4 h. The compn. of the reaction mixt. was detd. by means of GC with an internal standard. The Zn content of the liq. samples was quantified by X-ray fluorescence. The highest yields of propylene carbonate were obtained in the presence of basic ZnCO₃ (78.9%) and ZnO (76.9%). ZnO losses after each reaction cycle amounted to 27.4-33.1%. The Zn dissolved in the reaction mixt. was removed with the aid of ion exchangers.

3

Utilization of Black Liquor as Urease Inhibitor for Ammonia Reduction

Sarwono Ariyanti, Widiantara Mohammad Dandy, Zahra Nurulbaiti Listyendah, Floresyona Dita, Suryawan I. Wayan Koko, Siagian Franky Michael Hamonangan, Septiariva Iva Yenis

Ecological Engineering & Environmental Technology

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2022

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Vol. 23, iss. 2

213--218

EN

Urea fertilizers in agricultural operations usually tend to produce large amounts of ammonia due to hydrolysis, therefore contribute to the air pollution. The purpose of this study was to study the potential black liquor from pulp industry as urease inhibitor. Characterization of the black liquor was carried out by Spectrophotometer Fourier Transform Infra-Red (FTIR) and Thermal Gravimetric Analyzer (TGA) instruments. Meanwhile, the determination of ammonia levels was carried out using UV-spectrophotometer. The black liquor used in this process contains OH stretching, C=O stretching, an aromatic ring vibration, ring vibration, and guaiacil ring vibration indicating the presence of lignin. TGA primary weight loss in black liquor occurs above 200 °C. The addition of urease enzymes to urea tends to increase the release of ammonia. Meanwhile, the results showed that black liquor could prevent the nitrogen loss of urea.

4

Porównanie w warunkach laboratoryjnych skuteczności inhibitorów ureazy NBPT oraz 2-NPT w ograniczaniu strat gazowych amoniaku z nawozów zawierających azot amidowy

Dawidowicz Michał, Igras Janusz, Rusek Piotr

Przemysł Chemiczny

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2020

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T. 99, nr 10

1518--1521

PL

Przedstawiono wyniki badań nad skutecznością inhibitorów ureazy NBPT i 2-NPT w ograniczaniu strat azotu z nawozów zawierających azot amidowy. Badaniom poddano nawozy Pulrea®(mocznik), RSM, RSMS oraz Pulaska®. Potwierdzono dużą skuteczność NBPT i 2-NPT w inhibitowaniu enzymatycznej reakcji rozkładu mocznika.

EN

Two urease inhibitors were added (0.1–0.25%) to 4 amide fertilizers to reduce NH₃ emissions. The reduction of NH₃ loss was not less than 77% when compared to the fertilizers without additives. The o-NO₂C₆H₄NHP(O)(NH₂)₂ inhibitor was more efficient than the com. BuNHP(S)(NH₂)₂ one.

5

Koncepcja wykorzystania mocznika do ograniczenia emisji NOₓ z kotłów biomasowych małej mocy

Gaze Błażej, Romański Leszek, Kułażyński Marek

Przemysł Chemiczny

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2020

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T. 99, nr 4

569--573

PL

Przeprowadzono badania nad trzema wariantami ograniczenia emisji NOₓ do atmosfery podczas spalania biomasy w kotle małej mocy. W wariancie pierwszym do komory spalania podawano mocznik w strumieniu sprężonego powietrza, w drugim roztwór mocznika wtryskiwano w okolice palnika biomasowego, a wariancie trzecim biopaliwo było spalane po wcześniejszym wymieszaniu go z mocznikiem. Wyznaczono rozkład temperatury w komorze spalania. Określono punkty podawania mocznika i roztworu mocznika w odpowiednim oknie temperaturowym. Zbadano skład chemiczny oraz zapylenie spalin. Wyznaczono stopnie zmniejszenia zanieczyszczeń i zasugerowano najlepsze rozwiązanie w perspektywie spełnienia wymogów dyrektywy Ecodesign.

EN

Wood pellets were burned after addn. of (NH₂)₂CO (0.5-2.5% by mass) in a low-power boiler under varying conditions. The 1st method was based on burning pellets in the presence of solid (NH₂)₂CO, which was fed in a stream of compressed air. The 2nd method consisted in the injection of (NH₂)₂CO soln. near the burner, and the 3rd one was based on the burning of pellets previously mixed with (NH₂)₂CO. In terms of NOₓ redn., the best results were obtained fot the 3rd method and the worst ones for the 2nd method. The addn. of (NH₂)₂CO 1.5 or 2.5% by mass was recommended. Particulate matter emission were higher at the 3rd method and lower at the other ones.

6

Effect of fuel type on the combustion reaction behavior, phase structure and morphology of Ni0.5Co0.5Fe2O4 nanoparticles

Sedghi Arman, Salehkooh Elham Akbari, Chadorbafzade Monireh

Materials Science Poland

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2020

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Vol. 38, No. 2

341--349

EN

Nickel-cobalt ferrite spinels are ferrimagnetic ceramic materials that possess a great potential for application in high-density magnetic media, recording, color imaging, ferrofluids, and high-frequency devices. A change of their structure from micro- to nano- improves their properties drastically, therefore many methods have been investigated to fabricate nanopowder of these spinels. Gel combustion method is one of them. In this research, Ni0.5Co0.5Fe2O4nanoparticles were fabricated via gel combustion method using metallic nitrates as an oxidant and citric acid, glycine and urea as fuels and the effects of fuel type on the reaction behavior, structure and morphology of Ni0.5Co0.5Fe2O4nanoparticles were investigated. The reaction behavior was studied by thermal analysis method (TGA-DTA), crystallite size of powders was characterized by X-ray diffraction (XRD) and their morphology was studied by FE-SEM. The results revealed that the reaction was initiated in urea, glycine and citric at 219 °C, 197 °C, 212 °C, respectively. Samples fabricated from glycine and citric acid had a pure spinel structure but the others fabricated with urea fuel had iron oxide impurity. The crystallite size of nickel cobalt ferrite nanoparticles was in the range of 58 nm to 64 nm and the nanoparticles were agglomerated.

7

Selective catalytic reduction of NO with ammoniaat low temperature over Cu-promotedand N-modified activated carbon

Saad Marwa, Białas Anna, Grzywacz Przemysław, Czosnek Cezary, Samojeden Bogdan, Motak Monika

Chemical and Process Engineering

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2020

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Vol. 41, nr 1

59–-67

EN

Catalytic properties of activated carbons oxidized, treated with N-compounds, and promoted withcopper were studied in selective catalytic reduction NOXby ammonia (NH3-SCR). The modificationof the catalysts consisted of a series of steps (pre-oxidation of activated carbon, impregnation with urea,impregnation with copper). The physicochemical properties of the obtained samples were determinedusing X-ray diffraction, FT-IR spectroscopy, and low-temperature N2sorption. The modification withcopper improved the catalytic activity and stability of the catalysts. All the functionalized carbon dopedwith copper reached more than 90% of NO conversion and CO2did not exceed 240 ppm at 220◦C.The sample doped with 5 wt.% Cu had the maximum NO conversion of 98% at 300◦C. The maximum N2O concentration detected for the same sample was only 55 ppm, which confirmed its selectivity.

8

Impact of solute exchange between erythrocytes and plasma on hemodialyzer clearance

Waniewski J., Poleszczuk J., Pietribiasi M., Debowska M., Wojcik-Zaluska A., Zaluska W.

Biocybernetics and Biomedical Engineering

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2020

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Vol. 40, no. 1

265--276

EN

The standard theory of mass transport in dialyzer for water solutions was extended for solutes distributed in both plasma (PW) and erythrocyte intracellular (EW) water. Blood flow was divided into two separate flows of PW and EW with the diffusive exchange of solutes across cellular membrane (CM). Diffusive permeability of CM for urea and creatinine were assumed according to literature data. Computer simulations based on partial differential equations demonstrated that urea diffuses fast across CM and can be approximately considered as distributed uniformly in both blood flow components. In contrast, creatinine can be considered as distributed only in PW flow during the passage along the dialyzer. Therefore, the traditional formula for dialyzer clearance can be applied for urea and creatinine with the adjustment of their effective ‘‘blood’’ flow, but not for solutes with intermediate molecular mass. In vivo clearances of urea and creatinine were, as expected, lower than the respective theoretical predictions based of the diffusive permeability, P, times membrane surface area, A, parameters, PA, for dialyzer membrane, estimated for water solutions, by 33.6 ± 10.9% for creatinine and 10.8 ± 9.4% for urea. The estimated in vivo PAs were for creatinine 65.4 ± 26.0% and for urea 32.0 ± 10.9% lower than in vitro values provided by manufacturers. The much higher drop in clinical clearance/PA for creatinine than for urea suggests that the exchange of creatinine between plasma and dialysis fluid needs to be adjusted for the reduction of the dialyzer membrane surface area, which is effectively available for creatinine, caused by the presence of erythrocytes.

9

The influence of urea and formaldehyde on enzymatic hydrolysis of cellulose

Marchwicka Monika, Lesiak Anna, Radomski Andrzej

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

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2020

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No. 110

92--96

EN

Effect of selected urea and formaldehyde concentrations on glucose yield of enzymatic hydrolysis of cellulose was investigated. Urea and formaldehyde were added separately at the concentrations of 0.001, 0.002 and 0.005 g/cm3. Glucose was determined by high-performance liquid chromatography (HPLC). It was found that the used concentrations of urea didn’t influence glucose yield. In the case of formaldehyde, the results vary between used concentrations. The glucose yield of enzymatic hydrolysis of cellulose with the highest investigated concentration of formaldehyde (0.005 g/cm3) decreased by 50 %.

PL

Wpływ mocznika i formaldehydu na hydrolizę enzymatyczną celulozy. Prezentowane badania miały na celu określenie wpływu wybranych dodatków mocznika i formaldehydu na wydajność glukozy w enzymatycznej hydrolizie celulozy. Mocznik oraz formaldehyd dodano osobno w stężeniach 0,001, 0,002 i 0,005 g/cm3. Wydajność glukozy po hydrolizie enzymatycznej oznaczano za pomocą wysokosprawnej chromatografii cieczowej (HPLC). Stwierdzono, że zastosowane stężenia mocznika nie miały wpływu na wydajność glukozy. W przypadku formaldehydu wyniki różnią się między zastosowanymi stężeniami. Wydajność glukozy hydrolizy enzymatycznej celulozy z największym badanym stężeniem formaldehydu (0,005 g/cm3) była prawie o połowę mniejsza w porównaniu do hydrolizy enzymatycznej celulozy bez formaldehydu.

10

Solid-State Mechanochemical Synthesis of Kaolinite-Urea Complexes for Application as Slow Release Fertilizer

AlShamaileh Ehab M., Al-Rawajfeh Aiman E., Alrbaihat Mohammad R.

Journal of Ecological Engineering

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2019

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Vol. 20, nr 9

267--276

EN

This study investigated a mechanochemical (MC) process for synthesizing a slow-release urea fertilizer by cogrinding the starting materials of (NH2)2CO and amorphous kaolinite in a planetary ball mill. The tests with kaolinite contents ranging from 25 to 75 wt. %, milling time ranging from 1 (h) to 3 (h) and mill rotational speeds from 200 to 700 rpm were performed to evaluate the incorporation of (NH2)2CO and release of nitrogen into the solution. The analyses conducted using XRD, TGA, FT-IR and KNDU (Kjeldahl Nitrogen Determination Unit) indicated that the MC process was successfully applied to incorporate (NH2)2CO into the amorphous kaolinite structure. The release of nitrogen from the system (kaolinite-(NH2)2CO) when dispersed in water for 24 h reached up to 20% at 25% wt of kaolinite. Moreover, under the milling speed conditions for the system (kaolinite–(NH2)2CO), release of nitrogen reached between 25 and 40%. These results indicated that the MC process can be developed to allow amorphous kaolinite to act as a carrier of nitrogen nutrients to be released slowly for use as fertilizer.

11

Moja droga do poliuretanów

Wirpsza Z.

Przemysł Chemiczny

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2018

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T. 97, nr 8

1205--1206

12

Relative Explosive Strength and Detonation Characteristics of Some Explosive Mixtures Containing Urea and Peroxides

Hussein A. K., Zeman S., Suceska M., Jungova M.

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

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2017

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Vol. 8, Nr 3 (29)

23--32

EN

Several mixtures, based on urea, urea hydrogen peroxide complex (UHP), triacetone triperoxide (TATP) with some inorganic oxidants were studied by means of ballistics mortar with TNT as a reference standard. The detonation pressure, P, detonation velocity, D, detonation heat, Q, and volume of gaseous product at standard temperature and pressure conditions (STP condition) were calculated by the mean of Explo5 V6.3. The relatively high explosive strength of some samples relative to the TNT charge, focuses on the positive influence of hydrogen peroxide presence in these mixtures, with advantage in the form of its complex with urea (i.e. as UHP). This influence connects with hydroxi-radical in the mixture under its initiation (as the first intermediate of this initiation reaction).

13

Phytoremediation of urea fertilizer factory wastewater by teak (Tectona grandis)

Yavari S., Malakahmad A., Sapari N. B.

Environment Protection Engineering

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2017

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Vol. 43, nr 4

5--15

EN

Urea manufacturing discharge contains a high load of nitrogen, a pollutant which needs advanced technologies to be reduced to desirable levels. However, these advanced technologies are expensive due to the complex process and cost of chemicals and maintenance. Phytoremediation has been recently considered for N removal from various wastewaters. However, the common phytoremediation plants (reeds and grasses) are not able to remove N effectively due to the recyclable nature of N through decomposition processes. Therefore, they require periodic harvestings which impose a high cost on system. In this study, the growth and phytoremediation potential of teak (Tectona grandis), a tropical timber plant, to treat the urea manufacturing wastewater was evaluated. Eight month old teak seedlings received 4 different concentrations of N in bench-scale constructed wetlands every 4 days for 8 weeks. The solution volumes supplied to each container and plant biomass, N recovery, and tissue nutrient concentration were measured. Teak plants showed an escalation in wastewater N uptake with increasing amount of supplied N. Total dry weight was positively correlated with total N supplied. Teak seedlings showed a considerable potential for removing nitrogen when they were supplied with up to 5 g N per pot volume (4 dm3) during a two-month experiment.

14

Wybrane rozwiązania z chemii i technologii polimerów

Wirpsza Z.

Przemysł Chemiczny

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2016

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T. 95, nr 9

1676--1678

PL

Dokonano przeglądu prac Autora i jego współpracowników, opublikowanych w latach 1967–2011, z zakresu wykorzystania mocznika w chemii polimerów. Z mocznika otrzymywano nie tylko żywice i tworzywa mocznikowo-formaldehydowe, ale także melaminę, a z niej żywice melaminowo-formaldehydowe, karbaminiany i poliuretany bezizocyjanianowe, cyjanamid i policyjanamid, kwas izocyjanurowy oraz kwas izocyjanowy i cyjaniany metali, a z nich z kolei izocyjaniany bezfosgenowe. Przedstawiono też reakcje karbidu oraz wykorzystanie tworzyw skóropodobnych i odpadów skór, frakcji glicerolowej z produkcji biodiesla, odpadów poliuretanów oraz skrobi.

EN

A review, with 62 refs., of author’s own papers and patents concerning the use of urea and waste materials in polymer chemistry.

15

Technologia wytwarzania nawozu typu superfosfatu mocznikowego w systemie ciągłego dozowania surowców

Schab S., Biskupski A., Rusek P.

Przemysł Chemiczny

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2016

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T. 95, nr 5

1000--1002

PL

Przedstawiono nową technologię produkcji granulowanych nawozów azotowo-fosforowych typu USP (urea-superphosphate) umożliwiającą wytwarzanie produktu w sposób ciągły (bez konieczności dojrzewania półproduktu). W procesie zachodzi rozkład surowców fosforowych roztworem mocznika w kwasie siarkowym przy wyższej zawartości wody w układzie reakcyjnym niż w znanych dotychczas rozwiązaniach technologicznych. Przedstawiono schemat blokowy instalacji oraz zalecane parametry procesowe.

EN

An industrial process for prodn. of urea-superphosphate fertilizer was improved to be carried out in a continuous manner. Urea and raw phosphate are pulped in concd. H2SO4. The resulting sludge is granulated, dried, classified, cooled and stored.

16

Badania wiązania mocznika w procesie otrzymywania nawozów mocznikowo-superfosfatowych

Sadłowski M., Grzmil B., Lubkowski K.

Przemysł Chemiczny

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2016

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T. 95, nr 1

114--117

PL

Badano zdolność mocznika do tworzenia połączeń addycyjnych ze składnikami pulp superfosfatowych, takimi jak CaSO4 nH2O (gdzie n = 0–2) i Ca(H2PO4)2⋅H22O. Reakcje prowadzono ucierając wysuszony nawóz superfosfatowy z mocznikiem w młynie moździerzowym lub dodając mocznik do reaktora rozkładu fosforytu kwasami (H2SO4 lub H3PO4). Skład fazowy produktów badano metodą dyfrakcji rentgenowskiej. Stwierdzono, że najłatwiej przebiega reakcja mocznika z Ca(H2PO4)2⋅H2O, a w dalszej kolejności z CaSO4⋅2H2O i CaSO4⋅0,5H2O. W żadnym z prowadzonych doświadczeń nie zaobserwowano reaktywności mocznika z bezwodnym CaSO4.

EN

Urea additive compds. with superphosphate pulp components (Ca(H2PO4)2⋅H2O and CaSO4⋅nH2O, where n = 0–2), were prepd. The exps. were carried out (i) by milling urea with a dry superphosphate fertilizer in a lab. mortar grinder or (ii) by urea addn. to the reactor after phosphate rock decompn. with H2SO4 or H3PO4. The phase compn. Of products was studied by X-ray powder diffraction method. Ca(H2PO4)2⋅H2O was more reactive than CaSO4⋅2H2O and CaSO4⋅0.5H2O in the urea complexation. The reactivity of anhyd. CaSO4 towards urea was not obsd. in any expt.

17

SCR systems for NOx reduction in heavy and light duty vehicles

Jaworski P., Jarosiński S., Cortes Capetillo A., Kapusta Ł. J., Ziółkowski A., Grzywnowicz R.

Combustion Engines

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2016

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R. 55, nr 1

32--36

EN

Air pollution has become an important worldwide problem. The European Commission credits road and water transport as the major source of NOx pollution, and of being responsible for around 50% of the total air pollution in urban areas. During the last decade, the use of SCR technologies have gained popularity as a method for NOx reduction, the technology is widely considered as one of the solutions for road transport emissions. This paper presents a review of the different SCR system designs derived from the various factors and regulations in the automotive industry which have influenced the technology, along with a parametric study of a proprietary SCR system for heavy duty application.

18

Urea in lake ecosystem: the origin, concentration and distribution in relation to trophic state of The Great Mazurian Lakes (Poland)

Siuda W., Kiersztyn B.

Polish Journal of Ecology

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2015

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Vol. 63, nr 1

110--123

EN

The distribution, concentrations and origin of urea were studied in surface and profundal waters of meso-eutrophic and highly eutrophic parts of The Great Mazurian Lake System (GMLS) during spring – autumn period. Urea concentrations varied from 0.25 µM in surface layer to 3.36 µM in profundal zone of studied lakes and were in the range of concentrations noted in other non-polluted freshwater habitats. In the photic zone of lakes of GMLS Urea N made up to 10 % the total DON pool and often exceeded 2-3 times of NH4+-N concentrations. Pattern of changes in urea concentrations observed during three-years study excludes external urea input and suggests supplementation of lake waters with this compounds by phytoplankton decomposition processes. Generally, urea concentrations were negatively correlated with the trophic state index calculated from “algal” as well as from “bacterial” determinants. However, more detailed analysis showed that the relationships between production and assimilation of urea by various plankton components as well as the ecological role of this compound in meso- and eutrophic lakes could be different.

19

Wpływ dodatku mocznika, azotanu sodu i glikolu etylenowego na właściwości reologiczne kleików skrobi kukurydzianej

Makowska A., Kubiak P., Białas W., Lewandowicz G.

Polimery

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2015

|

T. 60, nr 5

343--350

PL

Zbadano wpływ substancji pomocniczych stosowanych w produkcji klejów skrobiowych na przebieg kleikowania oraz właściwości reologiczne natywnej skrobi kukurydzianej. Zawiesiny natywnej skrobi kukurydzianej, odmiany koński ząb, poddawano kleikowaniu w wiskografie RVA, a następnie umieszczano w cylindrze pomiarowym reometru HAAKE i badano lepkość w trybie kontrolowanej szybkości ścinania (CR). Do sporządzania zawiesin skrobiowych stosowano wodę destylowaną, roztwory mocznika, azotanu(V) sodu i glikolu etylenowego. Gotowe kleiki analizowano metodą rozmazu mikroskopowego, po wybarwieniu za pomocą płynu Lugola. Stwierdzono, że dodatek mocznika powoduje obniżenie temperatury kleikowania, zmianę kształtu krzywej kleikowania skrobi oraz wzrost lepkości końcowej otrzymanego kleiku. Stwierdzono, że dodatek azotanu(V) sodu powoduje wydłużenie czasu kleikowania i stabilizuje lepkość. Glikol etylenowy dodany do zawiesiny wywiera mniejszy wpływ na kleikowanie skrobi niż mocznik i azotan. Skrobia kukurydziana tworzy kleiki lub zawiesiny rozrzedzane ścinaniem, których właściwości reologiczne wyraźnie zmieniają się w czasie.

EN

The effects of the additives used in starch adhesives production on the pasting process and rheological properties of native corn starch were investigated. Suspensions of the starch of Indentata variety (6 %) prepared in distilled water or aqueous solutions of urea (2.5 %), sodium nitrate(V) (2.5 %) and ethylene glycol (1.5 %) were subjected to a controlled pasting in RVA viscometer. The obtained pastes were placed in a measuring cylinder of HAAKE rheometer and the viscosity measurements were performed using controlled shear rate (CR) mode at shear rates of 0—600 s-1. The paste smears were analyzed under a microscope after staining with Lugol's solution. It was found that the addition of urea caused a reduction in the pasting temperature, change in the shape of pasting curve as well as 30 % increase in the final viscosity (Table 1). The addition of sodium nitrate(V) led to an increase in the pasting time, decrease of the viscosity drop and reduced viscosity increase during cooling (Fig. 1). The influence of ethylene glycol additive on the pasting process was less significant than that of urea and sodium nitrate(V). Corn starch forms pastes or shear thinning suspensions with a distinct change in the rheological properties over time.

20

SCR systems for NOx reduction in heavy duty vehicles

Jaworski P., Kapusta Ł. J., Jarosiński S., Ziółkowski A., Cortes Capetillo A., Grzywnowicz R.

Journal of KONES

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2015

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Vol. 22, No. 4

139--146

EN

Air pollution has become an important worldwide problem. The European Commission credits road and water transport as the major source of NOx pollution, and of being responsible for around 50% of the total air pollution in urban areas. In Poland, around 45% of the country NOx emissions are attributed to transportation. During the last decade, the use of SCR technologies have gained popularity as a method for NOx reduction, the technology is widely considered as one of the solutions for road transport emissions. SCR technology had previously been employed in stationary plants, maritime transportation and other installations using combustion processes in which exhaust conditions are easier to control. The advance on the technology led to the introduction of the first heavy-duty vehicle with an SCR system into the market in 2004. New technologies and applications are constantly appearing, for example, SCR exhaust gas cleaning systems for reciprocating engines are still under development and compression ignition engines can be found in a number of different applications. The technology still needs to be studied and improved as constant problems and knowledge is required in issues such as urea injection, crystallization and NOx reduction efficiency. Moreover, the designs intended for heavy duty vehicles need to meet vehicle limitations and EURO emissions restrictions. This paper presents a review of the different SCR system designs derived from the various factors and regulations in the automotive industry, which have influenced the technology, along with a parametric study of a proprietary SCR system for heavy-duty application.